A097707 Part of n! composed of prime factors of form 4k+3.

1, 1, 3, 3, 3, 9, 63, 63, 567, 567, 6237, 18711, 18711, 130977, 392931, 392931, 392931, 3536379, 67191201, 67191201, 1411015221, 15521167431, 356986850913, 1070960552739, 1070960552739, 1070960552739, 28915934923953

Offset

1,3

Comments

log(a(n)) ~ 1/2 log n!.

Links

Table of n, a(n) for n=1..27.

P. Pollack, Analytic and Combinatorial Number Theory Course Notes, p. 75. [?Broken link]

P. Pollack, Analytic and Combinatorial Number Theory Course Notes, p. 75.

Prog

(PARI) a(n)=local(f); f=factor(n!); prod(k=1, matsize(f)[1], if(f[k, 1]%4<>3, 1, f[k, 1]^f[k, 2]))

Crossrefs

Equals A097706(A000142(n)).

Sequence in context: A299189 A231651 A160589 * A240533 A115282 A321507

Adjacent sequences: A097704 A097705 A097706 * A097708 A097709 A097710

Keyword

nonn

Author

Ralf Stephan, Aug 30 2004

Extensions

Typo in PARI code fixed by Colin Barker, Mar 12 2015

Status

approved